CLOUDSTACK-4531: Resolved ssh error for basic zone. Public ip should be used for ssh instead of ipaddress of nic

Signed-off-by: venkataswamybabu budumuru <venkataswamybabu.budumuru@citrix.com>
(cherry picked from commit 4f3b411d4cf9a6986337dea98cd902b25efefb95)